This is an interesting take on how a PLE can work in a school environment. Students can use their PLN as a collection system for information when they are doing their projects.
Under PLN Strategies there are some really good resources on how to create a personal learning plan, and some experiments on PLN's as professional development.
People to People seems to use the connectivist learning theory quite a bit. It is all about using other peoples information to help rather than using resources to re-research the same information. This is a pretty neat group.